1-(2-Tetrahydrofuryl)-5-fluorouracil is a known compound having cytostatic activity and slight toxicity [see Doklady Akademii Nauk SSSR, 176, 332-335 (1967)]. The compound has, however, hitherto been known only as the racemate since the previous processes for its manufacture are not stereospecific (see, for example, United States Patent No. 3,635,946, Belgian Pat. No. 807,556 and Japanese Patent Application No. 116079/1973) and the racemate cannot readily be split into the optical antipodes because of the absence of suitable acidic or basic substituents in the molecule. Also, the enzymatic cleavage of the racemate with glycosidases has been found, because of slight specificity, to be unsuitable for the manufacture of the antipodes in pure form, irrespective of the fact that thereby one of the two anomers disappears.